Browsing by Author "Tu, Z."

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    Combined Measurement of the Higgs Boson Mass in pp Collisions at √s=7 and 8 TeV with the ATLAS and CMS Experiments
    (American Physical Society, 2015) Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K.M.; Geurts, F.J.M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B.P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.
    A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the H→γγ and H→ZZ→4ℓ decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is mH=125.09±0.21 (stat)±0.11 (syst)  GeV.
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    Tunable unconventional kagome superconductivity in charge ordered RbV3Sb5 and KV3Sb5
    (Springer Nature, 2023) Guguchia, Z.; Mielke, C.; Das, D.; Gupta, R.; Yin, J.-X.; Liu, H.; Yin, Q.; Christensen, M.H.; Tu, Z.; Gong, C.; Shumiya, N.; Hossain, Md Shafayat; Gamsakhurdashvili, Ts; Elender, M.; Dai, Pengcheng; Amato, A.; Shi, Y.; Lei, H.C.; Fernandes, R.M.; Hasan, M.Z.; Luetkens, H.; Khasanov, R.
    Unconventional superconductors often feature competing orders, small superfluid density, and nodal electronic pairing. While unusual superconductivity has been proposed in the kagome metals AV3Sb5, key spectroscopic evidence has remained elusive. Here we utilize pressure-tuned and ultra-low temperature muon spin spectroscopy to uncover the unconventional nature of superconductivity in RbV3Sb5 and KV3Sb5. At ambient pressure, we observed time-reversal symmetry breaking charge order below $${T}_{{{{{{{{\rm{1}}}}}}}}}^{*}\simeq$$110 K in RbV3Sb5 with an additional transition at $${T}_{{{{{{{{\rm{2}}}}}}}}}^{*}\simeq$$50 K. Remarkably, the superconducting state displays a nodal energy gap and a reduced superfluid density, which can be attributed to the competition with the charge order. Upon applying pressure, the charge-order transitions are suppressed, the superfluid density increases, and the superconducting state progressively evolves from nodal to nodeless. Once optimal superconductivity is achieved, we find a superconducting pairing state that is not only fully gapped, but also spontaneously breaks time-reversal symmetry. Our results point to unprecedented tunable nodal kagome superconductivity competing with time-reversal symmetry-breaking charge order and offer unique insights into the nature of the pairing state.